- ~2.5 seconds for INSERT/VALUES
- ~10 seconds for prepared statement executes
- ~15 seconds for multiple INSERTs
Dan.
On Thu, May 10, 2012 at 3:42 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote:
Alban Hertroys <haramrae@xxxxxxxxx> writes:There is no planning associated with checking unique constraints; that's
> On 10 May 2012 15:05, Radosław Smogura <rsmogura@xxxxxxxxxxxxxxx> wrote:
>> May I ask what kind of planning may occur during insert?
> Well, for example, if there's a unique constraint on the table then
> the database will have to check that the newly inserted values don't
> conflict with values that are already in the table. It needs to plan
> an efficient strategy for that, which depends on the values being
> inserted.
just a matter for the index mechanisms.
I think the real point here is that a simple INSERT/VALUES has such a
trivial plan that there is hardly any gain to be had by avoiding the
planning stage. Then the other overhead of a prepared statement
(looking up the saved plan, checking it's not stale, etc) outweighs
that. Or at least it could. 3x slower seems a bit fishy; I wonder
whether there's some client-side inefficiency involved in that.
Doing performance measurements with pgAdmin seems pretty questionable
in the first place ...
regards, tom lane
